In contemporary telephone systems, the telephone user addresses other radio telephone units or land-line telephones by entering a telephone number that corresponds to the phone system address of the user to be contacted. Once the connection is complete, two way voice or data communications can take place.
With the widespread use of of cellular telephone systems in automobiles and other transportation means as a mode of communication, there have been a number of accidents or near accidents caused by cellular telephone users that have had to look at their set for an extended period of time while dialing a phone number. In order to make the task of dialing an access number easier, manufacturers added a memory feature to their telephones. This memory feature enables a user to recall pre-programmed numbers for automatic dialing. The present memory dialing method works fine when the user is in the geographic region covered by his or her primary service carrier. However, when the user is "roaming," that is, the user leaves the area in which the user's primary carrier is operating, the user is sometimes required to prefix the stored numbers with an additional access code. With typical PSTN (public switched telephone network) access numbers being seven digits in length and area codes being three digits, cellular telephone users generally program their unit's memory with a seven or ten digit number. When additional digits, such as a system access code are needed, the user must either enter the entire number manually or by storing multiple numbers, thus wasting valuable memory slots. As can be appreciated, none but the most talented users can safely enter a long phone number while driving in rush hour traffic without risking an accident.
Some cordless telephones, particularly those conforming to the Pan-European CT-2 specification, are capable of receiving a selective call numeric message representing a phone number where the message originator can be reached. This can be used to create a "pseudo" inbound calling capability by utilizing the received number presented in the message to originate a return call when the user reaches a Telepoint. Upon receiving the page, the user would see the call-back number, travel into range of a call-point, then activate a transmitter to originate a call to the number specified by the displayed message. However, this simple scenario does not address the requirements of modifying the received number to include toll, area, or other access codes. Regrettably, the only method available in a contemporary cordless telephone technology to modify a number is to delete the current last digit (at the cursor pointer) or complete telephone number.